The following technique in which a diaphragm facing a pump chamber (diaphragm pump) is used as an electric pump which drives the pump by converting the drive of the motor into a reciprocating motion of connecting rods by a crank mechanism is proposed.
A motor includes a rotor and a stator in a motor casing, a rotor shaft extended from the motor casing to a pump-body side and a motor driving circuit substrate. One ends of a pair of connecting rods are respectively assembled to the rotor shaft extended to the pump-body side through a pair of bearings. The pair of connecting rods are respectively assembled to positions where phases are shifted by 180 degrees. The other ends of the pair of connecting rods are respectively coupled to diaphragms through retainers. The diaphragm, a valve seat and a pump head portion are assembled to the pump body. A cylindrical eccentric shaft for cancelling the eccentricity of the pair of connecting rods is assembled to the vicinity of a shaft end of the rotor shaft extended on the pump-body side, and the connecting rods are assembled to the eccentric shaft through the bearings.
When the motor in the motor casing is rotated, the eccentric shaft attached to the rotor shaft extended on the pump body is also rotated, thereby reciprocating the connecting rods. At this time, the diaphragm is deformed and fluid in a pump chamber is discharged and sucked through a valve and a fluid passage (refer to Patent Literature 1).